The expression of the hemagglutinins of Avian influenza virus H5 H7and H9 subtypes was studied in this article by Pichia pastoris, one of the eukaryotis expression systems. Three reconstructed expression plasmids and engineering strains, named pPIC9K-H5HA, pPIC9K-H7HA, pPIC9K-H9HA and GS115/pPIC9K-H5HA, GS115/pPIC9K-H7HA, GS115/pPIC9K-H9HA repectively, were obtained. The reconstructed yeast engineering strains were identified by MD and MM plate selecting and PCR. The induced interests proteins were examined by SDS-PAGE and Western-bloting,the results showed that the interest genes were expressed exactly. And this will be helpful in the future study of antigen detection and antibody detection kit, as well in the subunit vaccines developing.
Animals ; Hemagglutinin Glycoproteins, Influenza Virus ; biosynthesis ; genetics ; Influenza A Virus, H5N1 Subtype ; genetics ; Influenza A Virus, H7N7 Subtype ; genetics ; Influenza A Virus, H9N2 Subtype ; genetics ; Pichia ; genetics ; metabolism

OBJECTIVETo identify genes in human cells infected with high pathogenic avian influenza viruses H5N1.

METHODSThe lung carcinoma cells line A549 was infected with H5N1 and H1N1, respectively. We harvested the infected cells at the different time points after infection and screened the genes with differential expression via microarray technology. The candidate genes were selected and confirmed by quantitative real-time PCR.

RESULTSThe spectrum of genes with the differential expression in the cells infected with H5N1 was obtained and 16 candidate genes were identified in the cellular apoptosis pathway, mTOR pathway, and the cellular immunity as well.

CONCLUSIONSOur results suggest that H5N1 exert a stronger impact on eliciting apoptosis of infected cells than the common influenza virus H1N1.

Animals ; Apoptosis ; Cell Line, Tumor ; Gene Expression Profiling ; Humans ; Influenza A Virus, H1N1 Subtype ; physiology ; Influenza A Virus, H5N1 Subtype ; physiology ; Influenza, Human ; genetics ; metabolism ; virology ; Oligonucleotide Array Sequence Analysis

We produced high pathogenic avian influenza H5N1 haemagglutinin protein HA1 in recombinant Pichia pastoris in a 10 L fermentor, to establish a high-density cell fermentation method. We studied the effects of different factors such as culture temperature, induced temperature, methanol feeding methods, trace elements on the growth of Pichia pastoris, the yield and the biologic activity of recombinant HA1 protein. The culture temperature in pre-induced and induced stage were optimized at 25 degrees C to adapt cell growth and recombinant protein expression, and induced temperature at 25 degrees C also resulted in higher biologic activity of rHA1 than at 30 degrees C. The binding activity of rHA1 against a wide-spectrum neutralizing antibody was susceptible to the presence of any trace elements, although trace elements would essentially benefit for the cell fermentation. As a conclusion, the expression level of rHA1 produced with optimized fermentation process reached 120 mg/L, which was 10.5 times higher than the one produced in regular shaking flask. The resultant high-density cell fermentation can likely produce rHA1 of H5N1 in large scale.
Fermentation ; Hemagglutinins, Viral ; biosynthesis ; genetics ; Influenza A Virus, H5N1 Subtype ; genetics ; metabolism ; Pichia ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis

OBJECTIVETo investigate the influence of avian influenza virus (AIV) NS1 protein on the expression of interferon-inducible protein 10 (IP-10).

METHODSNSI gene from virus A/Anhui/1/2005 (H5N1), NS1 gene inserted with 80-84 amino acids from virus A/Anhui/1/2005 (H5N1) and NS1 gene from virus A/Puerto Rico/8/1934 (H1N1) were cloned into the eukaryotic expression vector pEGFP-N1, and transfected into BEAS-2B cells, IP-10 expression level in transfected cells was detected by flow cytometry.

RESULTSCompared with the control group pEGFP-N1, expression of these three different NS1 genes can down-regulate the expression of IP-10 in BEAS-2B cells, but there is no significant difference as to the lower level among them.

CONCLUSIONNS1 protein of A/Anhui/1/2005 (H5N1) can down-regulate the expression level of IP-10, but this may not clarify its relationship with the virulence of AIV.

Cell Line ; Chemokine CXCL10 ; genetics ; metabolism ; Down-Regulation ; Gene Expression ; Humans ; Influenza A Virus, H5N1 Subtype ; genetics ; metabolism ; Influenza, Human ; genetics ; metabolism ; virology ; Viral Nonstructural Proteins ; genetics ; metabolism

This study aims to investigate the virological impact of the stalk region and cysteine (C) in neuraminidase (NA) of influenza A/Anhui/1/05 (H5N1) and A/Ohio/07/2009 (H1N1) viruses. The NA of A/ Anhui/1/05 (H5N1), defined as AH N1, lacked 20 amino acids (including C, defined as s20) as compared with NA of A/Ohio/07/2009 (H1N1) (defined as 09N1). We deleted s20 of 09N1 to construct 09N1-s20, and inserted s20 into AH N1 to construct AH N1+s20. To investigate the impact of C on the biological function of NA, we deleted C in 09N1 to construct 09N1-C and inserted C into AH N1 to construct AH N1-C. The pseudo-type viral particle (pp) system was used to evaluate the impact of these mutants on virology. The combination of 09N1-C and 09H1 (defined as 09H1::09N1-C) showed an infectivity 8 times that of the wild type 09H1::09N1, while the infectivity of the combination of AH N1+C and AH H5 (defined as AH H5::AH N1+C) was much lower than that of the wild type AH H5::AH N1. The infectivity of the combination of 09N1-s20 and 09H1 (defined as 09H1::09N1-s20) was 4 times that of the wild type 09H1::09N1; the infectivity of the combination of AH N1+s20 and AH H5 (defined as AH H5:: AH N1+s20) was 1/7 that of the wild type AH H5::AH N1. The co-existence of 09N1-C and AH H5 displayed 6 times the infectivity of AH H5::09N1, while the infectivity of 09H1::AH N1+C was very low. Multimer analysis showed that in the wild type 09N1, the forms of NA were dimer > tetramer > monomer; the major component of NA in 09N1-C was monomer; in 09N1-s20, the forms of NA were monomer > dimer. AH N1 was mainly composed of monomer; in AH N1+s20, the forms of NA were dimer > monomer > tetramer; in AH N1+C, the forms of NA were dimer > tetramer. Deletion of C or s20 from 09N1 did not change the expression of NA. The study suggested that deletion of C from the stalk region of NA in A/Ohio/07/2009 (H1N1) increases infectivity. Insertion of C into NA's stalk region of A/ Anhui/1/05 (H5N1) significantly decreases infectivity. Cysteine deletion in the stalk region is important for the infectivity of A/Anhui/1/05 (H5N1) and A/Ohio/07/2009 (H1N1). It may interfere with the infectivity via changes in NA polymerization.
Amino Acid Motifs ; Humans ; Influenza A Virus, H1N1 Subtype ; chemistry ; enzymology ; genetics ; pathogenicity ; Influenza A Virus, H5N1 Subtype ; chemistry ; enzymology ; genetics ; pathogenicity ; Influenza, Human ; virology ; Neuraminidase ; chemistry ; genetics ; metabolism ; Viral Proteins ; chemistry ; genetics ; metabolism ; Virulence

OBJECTIVETo prepare the 4 candidate vaccine strains of H5N1 avian influenza virus isolated in China.

METHODSRecombinant viruses were rescued using reverse genetics. Neuraminidase (NA) and hemagglutinin (HA) segments of the A/Xinjiang/1/2006, A/Guangxi/1/2009, A/Hubei/1/2010, and A/Guangdong/1/2011 viruses were amplified by RT-PCR. Multibasic amino acid cleavage site of HA was removed and ligated into the pCIpolI vector for virus rescue. The recombinant viruses were evaluated by trypsin dependent assays. Their embryonate survival and antigenicity were compared with those of the respective wild-type viruses.

RESULTSThe 4 recombinant viruses showed similar antigenicity compared with wild-type viruses, chicken embryo survival and trypsin-dependent characteristics.

CONCLUSIONThe 4 recombinant viruses rescued using reverse genetics meet the criteria for classification of low pathogenic avian influenza strains, thus supporting the use of them for the development of seeds and production of pre-pandemic vaccines.

Animals ; Chick Embryo ; Chickens ; China ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; metabolism ; Influenza A Virus, H5N1 Subtype ; immunology ; Influenza Vaccines ; immunology ; Influenza in Birds ; prevention & control ; virology ; Neuraminidase ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Vaccines, Synthetic ; immunology

HA and M2 genes derived from human highly pathogenic avian influenza H5N1 virus (A/Anhui/ 1/2005) isolated from China, were amplified and cloned into the DNA vaccine expression vector pVRC. In order to improve the expression of hemagglutinin, the human codon usage preference was made and the whole length of HA gene of H5NI (A/Anhui/1/2005) influenza virus was synthesized,named HA/YH/K, and inserted to pVRC vector, the expression of HA/YH/K protein in eukaryotic cells was significantly improved according to internal control of actin protein. Furthermore, the M2 and HA/YH/K genes were cloned into bicistronic eukaryotic expressing vector pIRES to yield the recombinant plasmid pIRES-HA/ YH/K-M2/YS/K, which could expressed HA and M2 protein simultaneously by transfection of one plasmid. Western blot and IFA showed that the recombinant pIRES-HA/YH/K-M2/YS/K plasmid was successfully expressed in several mammalian cells (Hela, MDCK and 293FT). The above results may help to identify the function and pathogenic mechanism of HA, M2 genes derived from HPAI H5N1 (Anhui strain) and pave a way for the development of novel bivalent vaccines against human highly pathogenic avian influenza virus and for preparedness for influenza pandemic.
Animals ; Cell Line ; Gene Expression ; Genetic Engineering ; Genetic Vectors ; genetics ; metabolism ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; metabolism ; Humans ; Influenza A Virus, H5N1 Subtype ; genetics ; isolation & purification ; metabolism ; Influenza, Human ; virology ; Recombinant Fusion Proteins ; genetics ; metabolism ; Viral Matrix Proteins ; genetics ; metabolism

OBJECTIVETo construct vectors expressing M2 and NA genes of H5N1 influenza virus.

METHODSBased on the human H5N1 avian influenza virus (A/Anhui/1/2005) isolated in china, M2 and NA genes were amplified by PCR. M2 or NA gene was subcloned into pStar vector to construct recombinant pStar-M2/, pStar-/M2, pStar-NA/and pStar-NA/. Furthermore, both of the M2 and NA genes were subcloned into pStar to construct two genes co-expressing recombinant pStar-M2/NA and pStar-NA/M2. Expression of the genes were detected by IFA after transfection of 293 cells with the recombinant plasmids.

RESULTSRecombinant plasmids were constructed and identified by restriction endonuclease digestion. Expression of the genes cloned into the recombinant plasmids was confirmed by IFA.

CONCLUSIONRecombinant plasmids expressing M2 and/or NA genes of H5N1 influenza virus were constructed, which provided basis for development of influenza DNA vaccine.

Cell Line ; Genetic Vectors ; genetics ; Humans ; Influenza A Virus, H5N1 Subtype ; genetics ; metabolism ; Neuraminidase ; genetics ; metabolism ; Plasmids ; genetics ; Viral Matrix Proteins ; genetics ; metabolism ; Viral Proteins ; genetics ; metabolism

OBJECTIVETo construct pseudovirus bearing H5N1 HA based on a lentivirus vector system. Then we study the biological feature of the pseudovirus. With the newly established viral particles, we performed the serological tests.

METHODSH5N1 avian influenza virus that isolated from human case was cloned to construct pLP-HA, then pLP-HA co-transfected with lentivirus vector plasmids pLP1, pLP2 and pEmGFP into 293T cells. The supernatant was harvested 48h post-transfection. Concentrated by super centrifuge, the pseudotyped viruses were analyzed by infection test, HA test and micro-neutralization test. At the same time, optimized HA gene and a Vietnam H5N1 HA gene were used to construct pseudotyped virus for comparison.

RESULTSPseudotyped virus particles can be observed with electronic microscope. Western-blot revealed that HA glycoprotein can be expressed in the virions. Our neutralization assay by using the pseudoviruses was comparable with the conventional microneutralization assay with wild-type viruses. A high degree of correlation was detected.

CONCLUSIONPseudotyped Viruses coated with HA of H5N1 High Pathogenic Avian Influenza were successfully constructed; it can be used to for the microneutralization assay. The HA gene from different sources affect the efficiency of the packaging of the pseudovirus. But the optimized HA gene can not obviously improve packaging efficiency of the pseudovirus.

Animals ; Cell Line ; Dogs ; Gene Expression ; Genetic Engineering ; Genetic Vectors ; genetics ; metabolism ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; metabolism ; Humans ; Influenza A Virus, H5N1 Subtype ; genetics ; physiology ; ultrastructure ; Influenza, Human ; virology ; Lentivirus ; genetics ; metabolism ; Virion ; genetics ; physiology ; ultrastructure

The distribution of glycosylation sites in HA proteins was various among H5 subtype avian influenza viruses (AIVs), however, the role of glycosylation sites to the virus is still unclear. In this study, avian influenza H5N1 viruses with deletion of the glycosylation sites in HA were constructed and rescued by site direct mutation and reverse genetic method, and their biological characteristics and virulence were determined. The result showed that the mutants were confirmed to be corrected by HA gene sequencing and Western blot analysis. The EID50 and TCID50 tested in SPF chick embryo and MDCK cells of a mutant rSdelta158 with deletion of glycosylation site at position 158 were slight lower than that of wild type rescued virus rS, and the plaque diameter of rSdelta158 was significant smaller than that of rS. The EID50 and TCID50 of mutants rSdelta169 and rSdelta290 with deletion of glycosylation sites at position 169 and 290, respectively, were slight higher than that of wild type rescued virus rS, the plaque diameters of rSdelta169 and rSdelta290 were similar as that of rS, but the plaque numbers of rSdelta169 and rSdelta290 were 10-fold higher than that to rS. On the other hand, the rSdelta158, rSdelta169 and rSdelta290 showed similar growth rate in chicken embryo fibroblast as rS. All viruses remained high pathogenicity to SPF chickens. Therefore, the growth of AIV can be affected by changes of glycosylation sites in HA protein, by which the effect is variable in different cells.
Amino Acid Motifs ; Animals ; Cell Line ; Chick Embryo ; Chickens ; Glycosylation ; Hemagglutinin Glycoproteins, Influenza Virus ; chemistry ; genetics ; metabolism ; Influenza A Virus, H5N1 Subtype ; chemistry ; genetics ; growth & development ; metabolism ; Influenza in Birds ; virology ; Poultry Diseases ; virology